商品经济产生和发展所需的经济条件包括()。A.社会产品数量的不断增加 B.社会产品种

—What does your mother do?

—She is ___.

A．reading

B．in the factory

C．a teacher

D．from the USA

—How is Sally?        

—____.      [ ]

A. She doesn’t know                  

B. She is my sister  

C. She is fine            

D. She is in her room.

汽车行驶系统有哪些功用？

居民医保缴费什么时候启动？不知参加居民医保最高报销限额是多少？

压缩机非正常停车先关闭末级排气切断阀，再切断主电机电源。